Leptin modulates human Sertoli cells acetate production and glycolytic profile: a novel mechanism of obesity-induced male infertility?

AbstractHuman feeding behavior and lifestyle are gradually being altered, favoring the development of metabolic diseases, particularly type 2 diabetes and obesity. Leptin is produced by the adipose tissue acting as a satiety signal. Its levels have been positively correlated with fat mass and hyperleptinemia has been proposed to negatively affect male reproductive function. Nevertheless, the molecular mechanisms by which this hormone affects male fertility remain unknown. Herein, we hypothesize that leptin acts on human Sertoli cells (hSCs), the “nurse cells” of spermatogenesis, altering their metabolism. To test our hypothesis, hSCs were cultured without or with leptin (5, 25 and 50ng/mL). Leptin receptor was identified by qPCR and Western blot. Protein levels of glucose transporters (GLUT1, GLUT2 and GLUT3), phosphofructokinase, lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were determined by Western Blot. LDH activity was assessed and metabolite production/consumption determined by proton nuclear magnetic resonance. Oxidative damage was evaluated by assessing lipid peroxidation, protein carbonilation and nitration. Our data shows that leptin receptor is expressed in hSCs. The concentration of leptin found in lean, healthy patients, upregulated GLUT2 protein levels and concentrations of leptin found in lean and obese patients increased LDH activity. Of note, all leptin concentrations decreased hSCs acetate production illustrating a novel mechanism for this hormone action. Moreover, our data shows that leptin does not induce or protect hSCs from oxidative damage. We report that this hormone modulates the nutritional support of spermatogenesis, illustrating a novel mechanism that may be linked to obesity-induced male infertility

Macrocalcitonin Is a Novel Pitfall in the Routine of Serum Calcitonin Immunoassay

Context: Calcitonin (CT) is a sensitive marker of medullary thyroid carcinoma (MTC) and is used for primary diagnosis and follow-up after thyroidectomy. However, persistently elevated CT is observed even after complete surgical removal without evidence of a recurrent or persistent tumor. Objective: To investigate the presence of assay interference in the serum CT of MTC patients who are apparently without a structural disease. Patients and Methods: We studied three index MTC cases for CT assay interference and 14 patients with metastatic MTC. The CT level was measured using an immunofluorometric assay. Screening for assay interference was performed by determination of CT levels before and after serum treatment with polyethylene glycol. Additionally, samples were analyzed by chromatography on ultra-performance liquid chromatography and protein A-Sepharose. Results: Patients with biochemical and structural disease showed CT mean recovery of 84.1% after polyethylene glycol treatment, whereas patients suspected of interference showed recovery from 2-7%. The elution profile on UPLC showed that the immunometric CT from these three patients behaved like a high molecular mass aggregate (>300 kDa). Additionally, when these samples were applied to the protein A-Sepharose, CT immunoreactivity was retained on the column and was only released after lowering the pH. Conclusions: For the first time, our results show the presence of a novel pitfall in the CT immunoassay: "macrocalcitonin." Its etiology, frequency, and meaning remain to be defined, but its recognition is of interest and can help clinicians avoid unnecessary diagnostic investigations and treatment during the follow-up of MTC.Sao Paulo State Research Foundation-FAPESPFAPESPFederal Agency of Support and Evaluation of Postgraduate Education (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior)National Council for Scientific and Technological DevelopmentUniv Fed Sao Paulo, Escola Paulista Med, Div Endocrinol, Dept Med,Thyroid Dis Ctr, BR-04039032 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Div Endocrinol, Dept Med,Lab Mol & Translat Endocrinol, BR-04039032 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Biochem, Div Mol Biol, BR-04044020 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Div Endocrinol, Dept Med,Thyroid Dis Ctr, BR-04039032 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Div Endocrinol, Dept Med,Lab Mol & Translat Endocrinol, BR-04039032 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Biochem, Div Mol Biol, BR-04044020 Sao Paulo, SP, BrazilFAPESP: 2006/60402-1FAPESP: 2010/51547-1FAPESP: 2010/19478Web of Scienc

Para o estudo da evolução do ensino e da formação em administração educacional em Portugal

Estudos sobre a evolução do ensino de disciplinas, na formação de professores em Portugal, são recentes. O controle burocrático centralizado reteve as dimensões do controle político-administrativo. De certo modo, protegeu a esfera educativa das influências modernizantes, do capitalismo industrial e das lógicas mercantis e gerencialistas. Defendeu a educação do domínio político, da intervenção de movimentos sociais, das propagandas de ideais democráticos e da cidadania. A utilização da designação "Administração educacional" ilustra as dificuldades sentidas, ao longo dos últimos anos, em termos da construção acadêmica de uma área, seja pela falta de tradição, seja pelos antecedentes históricos.In Portugal, studies about the evolution of disciplines teaching in the teachers formation are recent. The centralized bureaucratic control has held back the dimensions of politic administrative control. In a certain way, it has protected the education against the new-fashioned influences, manufacturing capitalism, and mercantile and managerial logics. This centralized bureaucratic control has also profected the education against the politic dominion, the intervention of social movements, the advertising of democratic ideals, and against the citizenship. The use of the term "Educational administration" shows the difficulties met by the searchers along the latest years, since there is no tradiction nor historic antecedence

Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

A Software Tool to Model Genetic Regulatory Networks. Applications to the Modeling of Threshold Phenomena and of Spatial Patterning in Drosophila

We present a general methodology in order to build mathematical models of genetic regulatory networks. This approach is based on the mass action law and on the Jacob and Monod operon model. The mathematical models are built symbolically by the Mathematica software package GeneticNetworks. This package accepts as input the interaction graphs of the transcriptional activators and repressors of a biological process and, as output, gives the mathematical model in the form of a system of ordinary differential equations. All the relevant biological parameters are chosen automatically by the software. Within this framework, we show that concentration dependent threshold effects in biology emerge from the catalytic properties of genes and its associated conservation laws. We apply this methodology to the segment patterning in Drosophila early development and we calibrate the genetic transcriptional network responsible for the patterning of the gap gene proteins Hunchback and Knirps, along the antero-posterior axis of the Drosophila embryo. In this approach, the zygotically produced proteins Hunchback and Knirps do not diffuse along the antero-posterior axis of the embryo of Drosophila, developing a spatial pattern due to concentration dependent thresholds. This shows that patterning at the gap genes stage can be explained by the concentration gradients along the embryo of the transcriptional regulators

Ancestry of the Brazilian TP53 c.1010G>A (p.Arg337His, R337H) founder mutation : clues from haplotyping of short tandem repeats on Chromosome 17p

Rare germline mutations in TP53 (17p13.1) cause a highly penetrant predisposition to a specific spectrum of early cancers, defining the Li-Fraumeni Syndrome (LFS). A germline mutation at codon 337 (p.Arg337His, c1010G>A) is found in about 0.3% of the population of Southern Brazil. This mutation is associated with partially penetrant LFS traits and is found in the germline of patients with early cancers of the LFS spectrum unselected for familial his- tory. To characterize the extended haplotypes carrying the mutation, we have genotyped 9 short tandem repeats on chromosome 17p in 12 trios of Brazilian p.Arg337His carriers. Results confirm that all share a common ancestor haplotype of Caucasian/Portuguese-Ibe- ric origin, distant in about 72–84 generations (2000 years assuming a 25 years intergenera- tional distance) and thus pre-dating European migration to Brazil. So far, the founder p. Arg337His haplotype has not been detected outside Brazil, with the exception of two resi- dents of Portugal, one of them of Brazilian origin. On the other hand, increased meiotic recombination in p.Arg337His carriers may account for higher than expected haplotype diversity. Further studies comparing haplotypes in populations of Brazil and of other areas of Portuguese migration are needed to understand the historical context of this mutation in Brazil.This study was funded by grant # 478430/2012-4 from CNPq (RFA MCT/CNPq - No 14/2012; Universal), Brazil.We would like to thank UFRGS, UFPA, AC Camargo, HC Barretos and University of Minho for their support during this work

Surface modification of starch based biomaterials by oxygen plasma or UV-irradiation

Radiation is widely used in biomaterials science for surface modification and sterilization. Herein, we describe the use of plasma and UV-irradiation to improve the biocompatibility of different starch-based blends in terms of cell adhesion and proliferation. Physical and chemical changes, introduced by the used methods, were evaluated by complementary techniques for surface analysis such as scanning electron microscopy, atomic force microscopy, contact angle analysis and X-ray photoelectron spectroscopy. The effect of the changed surface properties on the adhesion of osteoblast-like cells was studied by a direct contact assay. Generally, both treatments resulted in higher number of cells adhered to the modified surfaces. The importance of the improved biocompatibility resulting from the irradiation methods is further supported by the knowledge that both UV and plasma treatments can be used as cost-effective methods for sterilization of biomedical materials and devices.I. P. thanks the FCT for providing her a postdoctoral scholarship (SFRH/BPD/8491/2002). This work was partially supported by FCT, through funds from the POCTI and/or FEDER programs, The European Union funded STREP Project HIPPOCRATES (NNM-3-CT-2003-505758) and the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

In silico pathway reconstruction: Iron-sulfur cluster biogenesis in Saccharomyces cerevisiae

BACKGROUND: Current advances in genomics, proteomics and other areas of molecular biology make the identification and reconstruction of novel pathways an emerging area of great interest. One such class of pathways is involved in the biogenesis of Iron-Sulfur Clusters (ISC). RESULTS: Our goal is the development of a new approach based on the use and combination of mathematical, theoretical and computational methods to identify the topology of a target network. In this approach, mathematical models play a central role for the evaluation of the alternative network structures that arise from literature data-mining, phylogenetic profiling, structural methods, and human curation. As a test case, we reconstruct the topology of the reaction and regulatory network for the mitochondrial ISC biogenesis pathway in S. cerevisiae. Predictions regarding how proteins act in ISC biogenesis are validated by comparison with published experimental results. For example, the predicted role of Arh1 and Yah1 and some of the interactions we predict for Grx5 both matches experimental evidence. A putative role for frataxin in directly regulating mitochondrial iron import is discarded from our analysis, which agrees with also published experimental results. Additionally, we propose a number of experiments for testing other predictions and further improve the identification of the network structure. CONCLUSION: We propose and apply an iterative in silico procedure for predictive reconstruction of the network topology of metabolic pathways. The procedure combines structural bioinformatics tools and mathematical modeling techniques that allow the reconstruction of biochemical networks. Using the Iron Sulfur cluster biogenesis in S. cerevisiae as a test case we indicate how this procedure can be used to analyze and validate the network model against experimental results. Critical evaluation of the obtained results through this procedure allows devising new wet lab experiments to confirm its predictions or provide alternative explanations for further improving the models